As is well known and made the subject of the prior art, the high affinity that Ag+ ions have to --SH and other groups makes it an efficient biocide. If hydrogen peroxide (H.sub.2 O.sub.2) is simultaneously added the former causes a catalytic reaction with the H.sub.2 O.sub.2 to increase the efficiency quite considerably as H.sub.2 O.sub.2 is also a biocide. As a result, this process can be used to sterilise drinking water, or water that may be in contact with humans, such as water in pools, spas and the like.
Various attempts have been made in the past to devise apparatus and methods for the effective use of metal ions of silver and copper with H.sub.2 O.sub.2, but for a number of reasons success has not been attained. In consequence, no marketable technology is currently available, due mainly to difficulties in handling the H.sub.2 O.sub.2 , and controlling the dosages required. Many prior proposals have involved usage systems requiring labour intensive packaging in an endeavour to achieve accurate levels of all three additives, namely Ag+, copper and H.sub.2 O.sub.2. For example, U.S. Pat. No. 2,105,835 of Krause prescribed individual packaging, using tablet form, enclosed in soluble wrappings which gradually dissolve, encased in soluble crystals, powder mixes, adding to ice, and so forth. Likewise, United Kingdom specification No. 432101 of Katadyn A, G, discloses the use of packets, tablets, pills, capsules or ampoules, soluble coating of crystals or gelatine. Thus in the prior art the dosing of metals and H.sub.2 O.sub.2 involved cumbersome procedures and apparatus, with the apparatus also being expensive to manufacture, and in the main only specific predetermined bodies of water could be treated.
A major problem with the prior art arose from the fact that the handling of H.sub.2 O.sub.2 to perform the aforementioned functions had been found dangerous and likely to prove harmful to users. The strength of H.sub.2 O.sub.2 required was between 30 to 50% strength, and this made it dangerous bearing in mind that H.sub.2 O.sub.2 at even 8% strength is an irritant to the skin and is corrosive at 20%. To dose any large amount of water, such as 50,000 liters, using 15% strength H.sub.2 O.sub.2 would require a massive volume of hydrogen peroxide, and obviously dosing with H.sub.2 O.sub.2 at 50% strength would pose a serious health threat to the user.